What a corporation genuinely changes
The headline is the rate: a roofing corporation's first $500,000 of active income is taxed at roughly 12.2% combined in Ontario, against personal marginal rates that climb far higher once a good season stacks onto other income. Profit retained at that rate is what buys next spring's materials and carries the crew through winter, the smoothing engine our tax planning page builds on.
Three quieter benefits matter in roofing specifically. Commercial property managers and general contractors often prefer contracting with a corporation, so the structure opens doors on ICI work. Contract and warranty claims sit against the company rather than your house, though nothing shields you from your own negligence, which is why insurance stays primary. And if you ever sell a qualifying company's shares, the lifetime capital gains exemption of $1.25 million exists; roofing companies do sell, usually to consolidators or key employees, and only companies kept clean for years qualify.
What it does not change: WSIB
Since January 1, 2013, WSIB coverage has been mandatory in construction. Sole proprietors, partners and independent operators must register, and the executive officers of a roofing corporation need coverage as well, so incorporating does not take you off the premium roll. One partner or executive officer per business can be exempted, but only if they do no construction work; the exemption is built for the person who genuinely runs the office.
Two consequences follow. First, roofing sits in one of the highest-priced WSIB rate classes there is, so premiums on your own reported earnings are a real cost of any structure, and how you pay yourself changes the premium base. That conversation belongs before the articles are filed, not after. Second, general contractors must hold a valid clearance certificate for you before they pay you, corporation or not, so an account in good standing is a condition of getting cheques, not a formality.
There is a quieter upside to getting this right. The premiums the corporation pays are deductible, and a roofing company with its own WSIB account, clearances and insurance is exactly what a general contractor's classification review wants to see when it asks whether you are a genuine subcontractor or someone's employee in disguise.
The one true exception is narrow: work done exclusively in home renovation, retained directly by the occupant, can fall outside mandatory coverage. Most roofing businesses mix in new-build subcontracts or commercial jobs that put them squarely inside it.
Sole proprietor versus incorporated roofer
| Question | Sole proprietor | Corporation |
|---|---|---|
| Tax on profit kept in the business | Your full marginal rate | About 12.2% on the first $500,000 |
| Seasonal smoothing | Limited; income lands in the year earned | Retain in-season, draw level pay all year |
| WSIB | Mandatory registration | Still mandatory for executive officers |
| T5018 duties | File if construction is your primary activity | Identical |
| Liability on contracts | Personal | Corporate, but your own negligence stays yours |
| Filings and cost | T1 with self-employment schedules | T2, corporate records, payroll accounts |
| Selling one day | Asset sale, fully taxable | Possible $1.25M LCGE on qualifying shares |
The honest threshold: incorporation starts paying when you consistently earn more than you spend personally, so there is profit to leave inside at the low rate. A roofer drawing out every dollar each winter gets the costs of a corporation without its main benefit.
Set-up in the right order
Our Incorporation service handles the sequence so nothing bites later:
- Articles with room to grow. Share classes that allow family ownership later, drafted knowing TOSI limits dividends to relatives who genuinely work in the business.
- CRA accounts before the first job. Corporate tax, payroll before the first pay run, and an information-return account so T5018 slips file cleanly.
- HST from day one. Roofing revenue is fully taxable at 13%, and the $30,000 small-supplier threshold arrives within weeks, so register immediately and recover the HST on the truck, tools and trailer.
- WSIB and insurance before the first shingle. Registration, classification and liability coverage in the corporation's name, so clearances exist when the first GC asks.
- Contracts moved properly. Quotes, warranties and supplier accounts in the corporate name, so the shield you paid for actually applies.
Where the salary-dividend mix and the winter draw schedule should land is planning work, and our Tax Planning & Advisory service picks that up the day the corporation exists. If you are weighing the move, a free 15-minute call through our contact page is enough to tell you whether the math is close.
